Measurement of Bivalirudin Thrombin Inhibition Activity in Plasma with Clotting or Chromogenic Assays and Dedicated Calibrators and Controls

Bivalirudin is a parenteral direct thrombin inhibitor anticoagulant and does not induce any impairment of the Protein C pathway, which function remains preserved. This drug meets increasing applications for cardiac surgery and heart diseases, especially when heparin is contra-indicated in presence of heparin-induced thrombocytopenia. Major indications concern Extra Corporeal Circulation, PCI/PTCA, and myocardial infarction. Drug clearance occurs partly through kidney. Patients with moderate or severe renal dysfunctions are exposed to drug accumulation and subsequent bleeding, the major adverse effect reported. This study presents 2 automated assays, a clotting method, and a kinetics chromogenic technique, proposed for the quantitative measurement of bivalirudin in citrated plasma. Both assays need a specific bivalirudin calibration, are fully automatable on coagulation instruments, and can be available at any time in specialized clinical laboratories for an on time monitoring of treated patients. Assay ranges are from 0.3 to 5.0 μg/ml (clotting assay) or to 6.0μg/ml (chromogenic assay), and up to 20.0μg/ml with an additional automatic plasma dilution. These methods offer excellent performances, with good reproducibility and repeatability. This study reports the results obtained with both assays on bivalirudin measurements in 26 treated patients collected at 4 timings. Both methods are fully consistent and contribute to facilitate and secure the use of this anticoagulant when it is indicated.

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Combined Thrombin and Platelet Inhibition Treatment for HIT Patients

Hämostaseologie ◽

10.1055/s-0038-1660400 ◽

1999 ◽

Vol 19 (03) ◽

pp. 128-133 ◽

Cited By ~ 1

Author(s):

B.E. Lewis ◽

W. P. Jeske ◽

F. Leya ◽

Diane Wallis ◽

M. Bakhos ◽

...

Keyword(s):

Standard Dose ◽

Combined Therapy ◽

Platelet Inhibition ◽

Thrombin Inhibitors ◽

Thrombin Inhibitor ◽

Heparin Induced Thrombocytopenia ◽

Acute Thrombosis ◽

Anti Platelet Drug ◽

Receptor Inhibitor

SummaryDespite the use of potent anticoagulants such as r-hirudin and argatroban, the morbidity and mortality in heparin-induced thrombocytopenia (HIT) patients remains unacceptable. Data from our in vitro investigations show that thrombin inhibitors do not block platelet activation induced by heparin antibodies and heparin but that GPIIb/IIIa receptor inhibitors do block this process. We have treated four HIT positive patients with a combined therapy of thrombin inhibitor and GPIIb/IIIa receptor inhibitor when treatment with thrombin inhibitor alone failed to alleviate acute thrombosis. Combination therapies included r-hirudin (Refludan®) with tirofiban (Aggrastat®) and argatroban (Novastan®) with abciximab (ReoPro®). A reduced dose of the thrombin inhibitor was used with the standard dose of the anti-platelet drug. In all cases, there was no overt bleeding which required intervention, and all patients exhibited clinical improvement or full recovery. These case studies suggest that treatment of active thrombosis in HIT patients with adjunct GPIIb/IIIa receptor inhibitor therapy may be more effective than thrombin inhibitor treatment alone.

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Evaluating Thrombin Inhibition in Alzheimer’s Disease (The BEACON Trial): Protocol for a Pilot Study (Preprint)

10.2196/preprints.14905 ◽

2019 ◽

Author(s):

Cláudia Yang Santos ◽

Christine Getter ◽

John Stoukides ◽

Brian Ott ◽

Stephen Salloway ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Pilot Study ◽

Cognitive Performance ◽

Thrombin Inhibitor ◽

Placebo Control ◽

Open Label ◽

Double Blind ◽

Thrombin Inhibition ◽

Approved Drugs

BACKGROUND The precise mechanisms whereby cardiovascular risk factors increase the risk of Alzheimer’s disease (AD) have not been delineated. We reported that microvessels isolated from AD brains overexpress a diverse array of neurotoxic and inflammatory proteins, which is consistent with the process of vascular activation. In pre-clinical studies using AD animal models we showed that a vascular activation inhibitor reduced vascular-derived neuroinflammation and improved cognitive performance. Thrombin is a key mediator of cerebrovascular activation in AD. OBJECTIVE This study aims to investigate the safety and potential efficacy of the direct thrombin inhibitor dabigatran, in patients with mild cognitive impairment (MCI) or mild AD to decrease vascular-derived neuroinflammation and improve cognitive performance. METHODS Participants will be enrolled then evaluated quarterly throughout the 24-month study. This is a 24-month randomized-control, double-blind, placebo-controlled, multicenter, delayed-start, pilot study evaluating thrombin inhibition in people with biomarker-confirmed MCI probably due to AD or mild AD. 40 - 60 participants will be recruited between 50 - 85 years old. In the initial 9-months of study, either dabigatran or placebo will be orally administered to patients at a dose of 150 mg per day. After 9 months of the placebo-control (Phase I), the placebo arm will cross-over to an active, open-label (Phase II) where all patients will be treated with a 150 mg daily dose of dabigatran orally for an additional 12 months. A 3-month non-treatment follow-up period will assess duration of effects. RESULTS Beginning in July 2019, and concluding in August 2022, this study is expected to publish final results in January 2023. CONCLUSIONS BEACON is a first-in-kind randomized clinical trial targeting thrombin activation in AD therapeutics. This trial will stimulate translational investigations of an FDA-approved drugs in a newly defined therapeutic areas. CLINICALTRIAL Clinicaltrials.gov NCT03752294

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Safety and Efficacy of Argatroban in the Management of Heparin-Induced Thrombocytopenia

Clinical medicine Blood disorders ◽

10.4137/cmbd.s5118 ◽

2011 ◽

Vol 4 ◽

pp. CMBD.S5118 ◽

Cited By ~ 1

Author(s):

Bernd Saugel ◽

Roland M. Schmid ◽

Wolfgang Huber

Keyword(s):

Arterial Thrombosis ◽

Pharmacokinetic Profile ◽

The United States ◽

Heparin Therapy ◽

Direct Thrombin Inhibitor ◽

Thrombin Inhibitor ◽

Heparin Induced Thrombocytopenia ◽

Safety And Efficacy ◽

Increased Risk ◽

Life Threatening

Heparin-induced thrombocytopenia (HIT) is a life-threatening adverse reaction to heparin therapy that is characterized by thrombocytopenia and an increased risk of venous and arterial thrombosis. According to guidelines, in patients with strongly suspected or confirmed HIT all sources of heparin have to be discontinued and an alternative, nonheparin anticoagulant for HIT treatment must immediately be started. For both the prophylaxis of thrombembolic events in HIT and the treatment of HIT with thrombosis the direct thrombin inhibitor argatroban is approved in the United States. The objective of this review is to describe the mechanism of action and the pharmacokinetic profile of argatroban, to characterize argatroban regarding its safety and therapeutic efficacy and to discuss its place in therapy in HIT.

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Heparin-induced Thrombocytopenia: Towards Consensus

Thrombosis and Haemostasis ◽

10.1055/s-0037-1614206 ◽

1998 ◽

Vol 79 (01) ◽

pp. 1-7 ◽

Cited By ~ 378

Author(s):

Theodore Warkentin ◽

Beng Chong ◽

Andreas Greinacher

Keyword(s):

Adverse Reaction ◽

Treatment Approach ◽

Diagnostic Testing ◽

Optimal Treatment ◽

Drug Induced ◽

Danaparoid Sodium ◽

Heparin Induced Thrombocytopenia ◽

Thrombin Inhibition ◽

Common Drug ◽

Thrombotic Complications

SummaryHeparin-induced thrombocytopenia (HIT) is a drug-induced, immunoglobulin-mediated thrombocytopenic disorder that is important for at least three reasons. First, it is a relatively common drug-induced immunohematologic adverse reaction. Second, it is frequently complicated by life- and limb-threatening thrombotic complications. And third, there remains uncertainty about the optimal treatment approach for these patients. Recently, there has emerged increasing consensus on such important issues as the frequency, pathogenesis, and diagnostic testing, which we will summarize here. Further, a greater appreciation of the activation of the coagulation pathways in this syndrome indicate a rationale to treatment approaches that emphasize thrombin inhibition (eg. danaparoid sodium; hirudin and its analogues).

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Argatroban and Renal Replacement Therapy in Patients with Heparin-Induced Thrombocytopenia

Annals of Pharmacotherapy ◽

10.1345/aph.1e480 ◽

2005 ◽

Vol 39 (2) ◽

pp. 231-236 ◽

Cited By ~ 60

Author(s):

Ignatius Y Tang ◽

Donna S Cox ◽

Kruti Patel ◽

Bharathi V Reddy ◽

Linda Nahlik ◽

...

Keyword(s):

At Risk ◽

Renal Replacement Therapy ◽

Replacement Therapy ◽

Direct Thrombin Inhibitor ◽

Thrombin Inhibitor ◽

Systemic Clearance ◽

Recovery Method ◽

P Values ◽

Heparin Induced Thrombocytopenia ◽

Alternative Anticoagulation

BACKGROUND: Argatroban, a direct thrombin inhibitor, is an effective anticoagulant for patients who have heparin-induced thrombocytopenia (HIT). Anticoagulation is usually required for renal replacement therapy (RRT). OBJECTIVE: To prospectively evaluate the pharmacokinetics, pharmacodynamics, and safety of argatroban during RRT in hospitalized patients with or at risk for HIT. METHODS: Five patients with known or suspected HIT underwent hemodialysis (n = 4) or continuous venovenous hemofiltration (CVVH, n = 1), while receiving a continuous infusion of argatroban 0.5–2 μg/kg/min. Activated partial thromboplastin times (aPTTs), activated clotting times (ACTs), argatroban concentrations (plasma, dialysate, CVVH effluent), and safety were assessed before, during, and after a 4-hour session of RRT. Systemic and dialytic argatroban clearances were calculated. RESULTS: Among the 4 hemodialysis patients, aPTT, ACT, and plasma argatroban concentrations remained stable during RRT, with respective mean ± SD values of 74.3 ± 34.2 seconds, 198 ± 23 seconds, and 499 ± 353 ng/mL before RRT, and 70.6 ± 21.4 seconds, 181 ± 12 seconds, and 453 ± 295 ng/mL 2 hours after starting RRT (p values NS). Systemic clearance was 17.7 ± 12.8 L/h before hemodialysis and 17.0 ± 9.5 L/h during hemodialysis (n = 2). The dialyzer clearance (dialysate recovery method) was 1.5 ± 0.4 L/h (n = 4). Generally similar responses occurred in the CVVH patient: systemic argatroban clearance was 4.8 L/h before CVVH and 4 L/h during CVVH. The hemofilter argatroban clearance was 0.9 L/h. No bleeding or thrombosis occurred. CONCLUSIONS: Argatroban provides effective alternative anticoagulation in patients with or at risk for HIT during RRT. Argatroban clearance by high-flux membranes during hemodialysis and CVVH is clinically insignificant, necessitating no dose adjustment.

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Diagnosis and treatment of heparin-induced thrombocytopenia

Perfusion ◽

10.1191/0267659103pf637oa ◽

2003 ◽

Vol 18 (1) ◽

pp. 47-53 ◽

Cited By ~ 6

Author(s):

William J DeBois ◽

Junli Liu ◽

Leonard Y Lee ◽

Leonard N Girardi ◽

Charles Mack ◽

...

Keyword(s):

New York ◽

Platelet Inhibition ◽

Heparin Therapy ◽

Serotonin Release ◽

Antibody Detection ◽

Thrombin Inhibitor ◽

Heparin Infusion ◽

Platelet Factor ◽

Heparin Induced Thrombocytopenia ◽

Life Threatening

Heparin-induced thrombocytopenia (HIT) is a major side effect secondary to the administration of heparin. This syndrome is serious and potentially life threatening. This response is the result of antibodies formed against the platelet factor 4 (PF4)/heparin complex. The incidence of this immune-mediated syndrome has been estimated to be 1-3% of all patients receiving heparin therapy. The occurrence of HIT in patients requiring full anticoagulation for cardiopulmonary bypass (CPB), therefore, presents a serious challenge to the cardiac surgery team. The diagnosis of HIT should be based on both clinical and laboratory evidence. While functional assays, platelet aggregation tests, and the serotonin release assay can be used to support the diagnosis, the negative predictive value of these tests is generally less than 50%. In contrast, although non-functional antibody detection assays are more sensitive, they have a low specificity. HIT can be treated in several ways, including cessation of all heparin and giving an alternative thrombin inhibitor, platelet inhibition followed by heparin infusion, and the use of low molecular weight heparins. In this presentation, the pathology and current diagnostic tests, as well as the successful management of patients with HIT undergoing CPB at New York Presbyterian Hospital, are reviewed.

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The Cardioprotective Signaling Activity of Activated Protein C in Heart Failure and Ischemic Heart Diseases

International Journal of Molecular Sciences ◽

10.3390/ijms20071762 ◽

2019 ◽

Vol 20 (7) ◽

pp. 1762 ◽

Cited By ~ 3

Author(s):

Di Ren ◽

Hemant Giri ◽

Ji Li ◽

Alireza R. Rezaie

Keyword(s):

Heart Failure ◽

Protein C ◽

Heart Diseases ◽

Ischemia Reperfusion ◽

Activated Protein C ◽

Ischemic Heart ◽

Signaling Networks ◽

Endothelial Protein C Receptor ◽

Signaling Mechanism ◽

Mtorc1 Signaling

Activated protein C (APC) is a vitamin-K dependent plasma serine protease, which functions as a natural anticoagulant to downregulate thrombin generation in the clotting cascade. APC also modulates cellular homeostasis by exhibiting potent cytoprotective and anti-inflammatory signaling activities. The beneficial cytoprotective effects of APC have been extensively studied and confirmed in a number of preclinical disease and injury models including sepsis, type-1 diabetes and various ischemia/reperfusion diseases. It is now well-known that APC modulates downstream cell signaling networks and transcriptome profiles when it binds to the endothelial protein C receptor (EPCR) to activate protease-activated receptor 1 (PAR1) on various cell types. However, despite much progress, details of the downstream signaling mechanism of APC and its crosstalk with other signaling networks are far from being fully understood. In this review, we focus on the cardioprotective properties of APC in ischemic heart disease and heart failure with a special emphasis on recent discoveries related to the modulatory effect of APC on AMP-activated protein kinase (AMPK), PI3K/AKT, and mTORC1 signaling pathways. The cytoprotective properties of APC might provide a novel strategy for future therapies in cardiac diseases.

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Endotoxin and thrombin elevate rodent endothelial cell protein C receptor mRNA levels and increase receptor shedding in vivo

Blood ◽

10.1182/blood.v95.5.1687.005k08_1687_1693 ◽

2000 ◽

Vol 95 (5) ◽

pp. 1687-1693 ◽

Cited By ~ 83

Author(s):

Jian-Ming Gu ◽

Yasuhiro Katsuura ◽

Gary L. Ferrell ◽

Paula Grammas ◽

Charles T. Esmon

Keyword(s):

Cell Culture ◽

Septic Shock ◽

Endothelial Cell ◽

Protein C ◽

Fold Increase ◽

Cell Protein ◽

Thrombin Inhibitor ◽

Mrna Levels ◽

Soluble Epcr

The endothelial cell protein C receptor (EPCR) facilitates protein C activation by the thrombin-thrombomodulin complex. Protein C activation has been shown to be critical to the host defense against septic shock. In cell culture, tumor necrosis factor- (TNF-) down-regulates EPCR expression, raising the possibility that EPCR might be down-regulated in septic shock. We examined EPCR mRNA and soluble EPCR levels in mice and rats challenged with lethal dose 95 levels of endotoxin. Toxic doses of TNF- failed to alter EPCR mRNA levels in mice. Rather than EPCR mRNA levels falling in response to endotoxin, as predicted from cell-culture experiments, they rose approximately 3-fold 6 hours after exposure to endotoxin before returning toward baseline levels at 24 hours after exposure. Soluble EPCR levels rose approximately 4-fold. Infusion of hirudin, a specific thrombin inhibitor, before endotoxin exposure almost completely blocked the increase in EPCR mRNA and soluble EPCR. Consistent with the idea that the responses were mediated by thrombin, thrombin infusion (5 U/kg of body weight for 3 hours) resulted in an approximately 2-fold increase in EPCR mRNA and soluble EPCR. Incubation of rat endothelial cells with thrombin or murine protease-activated receptor 1 agonist peptide resulted in a 2-fold increase in EPCR mRNA. These results indicate that thrombin plays a major role in up-regulating EPCR mRNA and shedding in vivo.

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